cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 16 results. Next

A000294 Expansion of g.f. Product_{k >= 1} (1 - x^k)^(-k*(k+1)/2).

Original entry on oeis.org

1, 1, 4, 10, 26, 59, 141, 310, 692, 1483, 3162, 6583, 13602, 27613, 55579, 110445, 217554, 424148, 820294, 1572647, 2992892, 5652954, 10605608, 19765082, 36609945, 67405569, 123412204, 224728451, 407119735, 733878402, 1316631730, 2351322765, 4180714647, 7401898452, 13051476707, 22922301583, 40105025130, 69909106888, 121427077241, 210179991927, 362583131144
Offset: 0

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Keywords

Comments

Number of partitions of n if there are k(k+1)/2 kinds of k (k=1,2,...). E.g., a(3)=10 because we have six kinds of 3, three kinds of 2+1 because there are three kinds of 2 and 1+1+1+1. - Emeric Deutsch, Mar 23 2005
Euler transform of the triangular numbers 1,3,6,10,...
Equals A028377: [1, 1, 3, 9, 19, 46, 100, ...] convolved with the aerated version of A000294: [1, 0, 1, 0, 4, 0, 10, 0, 26, 0, 59, ...]. - Gary W. Adamson, Jun 13 2009
The formula for p3(n) in the article by S. Finch (page 2) is incomplete, terms with n^(1/2) and n^(1/4) are also needed. These terms are in the article by Mustonen and Rajesh (page 2) and agree with my results, but in both articles the multiplicative constant is marked only as C, resp. c3(m). The following is a closed form of this constant: Pi^(1/24) * exp(1/24 - Zeta(3) / (8*Pi^2) + 75*Zeta(3)^3 / (2*Pi^8)) / (A^(1/2) * 2^(157/96) * 15^(13/96)) = A255939 = 0.213595160470..., where A = A074962 is the Glaisher-Kinkelin constant and Zeta(3) = A002117. - Vaclav Kotesovec, Mar 11 2015 [The new version of "Integer Partitions" by S. Finch contains the missing terms, see pages 2 and 5. - Vaclav Kotesovec, May 12 2015]
Number of solid partitions of corner-hook volume n (see arXiv:2009.00592 among links for definition). E.g., a(2) = 1 because there is only one solid partition [[[2]]] with cohook volume 2; a(3) = 4 because we have three solid partitions with two 1's (entry at (1,1,1) contributes 1, another entry at (2,1,1) or (1,2,1) or (1,1,2) contributes 2 to corner-hook volume) and one solid partition with single entry 3 (which contributes 3 to the corner-hook volume). Namely as 3D arrays [[[1],[1]]],[[[1]],[[1]]],[[[1]],[[1]]], [[[3]]]. - Alimzhan Amanov, Jul 13 2021

References

  • R. Chandra, Tables of solid partitions, Proceedings of the Indian National Science Academy, 26 (1960), 134-139.
  • V. S. Nanda, Tables of solid partitions, Proceedings of the Indian National Science Academy, 19 (1953), 313-314.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. also A278403 (log of o.g.f.).

Programs

  • Maple
    with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: a:= etr(n-> n*(n+1)/2): seq(a(n), n=0..30);  # Alois P. Heinz, Sep 08 2008
  • Mathematica
    a[0] = 1; a[n_] := a[n] = 1/(2*n)*Sum[(DivisorSigma[2, k]+DivisorSigma[3, k])*a[n-k], {k, 1, n}]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Mar 05 2014, after Vladeta Jovovic *)
    nmax=50; CoefficientList[Series[Product[1/(1-x^k)^(k*(k+1)/2),{k,1,nmax}],{x,0,nmax}],x] (* Vaclav Kotesovec, Mar 11 2015 *)
  • PARI
    a(n)=if(n<0, 0, polcoeff(exp(sum(k=1, n, x^k/(1-x^k)^3/k, x*O(x^n))), n)) \\ Joerg Arndt, Apr 16 2010
    
  • SageMath
    # uses[EulerTransform from A166861]
    b = EulerTransform(lambda n: binomial(n+1, 2))
    print([b(n) for n in range(37)]) # Peter Luschny, Nov 11 2020

Formula

a(n) = (1/(2*n))*Sum_{k=1..n} (sigma[2](k)+sigma[3](k))*a(n-k). - Vladeta Jovovic, Sep 17 2002
a(n) ~ Pi^(1/24) * exp(1/24 - Zeta(3) / (8*Pi^2) + 75*Zeta(3)^3 / (2*Pi^8) - 15^(5/4) * Zeta(3)^2 * n^(1/4) / (2^(7/4)*Pi^5) + 15^(1/2) * Zeta(3) * n^(1/2) / (2^(1/2)*Pi^2) + 2^(7/4) * Pi * n^(3/4) / (3*15^(1/4))) / (A^(1/2) * 2^(157/96) * 15^(13/96) * n^(61/96)), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant and Zeta(3) = A002117 = 1.202056903... . - Vaclav Kotesovec, Mar 11 2015
G.f.: exp(Sum_{k>=1} (sigma_2(k) + sigma_3(k))*x^k/(2*k)). - Ilya Gutkovskiy, Aug 21 2018

Extensions

More terms from Sascha Kurz, Aug 15 2002

A000335 Euler transform of A000292.

Original entry on oeis.org

1, 5, 15, 45, 120, 331, 855, 2214, 5545, 13741, 33362, 80091, 189339, 442799, 1023192, 2340904, 5302061, 11902618, 26488454, 58479965, 128120214, 278680698, 602009786, 1292027222, 2755684669, 5842618668, 12317175320, 25825429276, 53865355154, 111786084504, 230867856903, 474585792077, 971209629993
Offset: 1

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Author

Keywords

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: a:= etr(n-> binomial(n+2,3)): seq(a(n), n=1..26); # Alois P. Heinz, Sep 08 2008
  • Mathematica
    max = 33; f[x_] := Exp[ Sum[ x^k/(1-x^k)^4/k, {k, 1, max}]]; Drop[ CoefficientList[ Series[ f[x], {x, 0, max}], x], 1](* Jean-François Alcover, Nov 21 2011, after Joerg Arndt *)
    nmax=50; Rest[CoefficientList[Series[Product[1/(1-x^k)^(k*(k+1)*(k+2)/6),{k,1,nmax}],{x,0,nmax}],x]] (* Vaclav Kotesovec, Mar 11 2015 *)
    etr[p_] := Module[{b}, b[n_] := b[n] = If[n==0, 1, Sum[DivisorSum[j, #*p[#] &]*b[n-j], {j, 1, n}]/n]; b]; a = etr[Binomial[#+2, 3]&]; Table[a[n], {n, 1, 40}] (* Jean-François Alcover, Nov 24 2015, after Alois P. Heinz *)
  • PARI
    a(n)=if(n<1, 0, polcoeff(exp(sum(k=1, n, x^k/(1-x^k)^4/k, x*O(x^n))), n)) /* Joerg Arndt, Apr 16 2010 */
    
  • PARI
    N=66; x='x+O('x^66); gf=-1 + exp(sum(k=1, N, x^k/(1-x^k)^4/k)); Vec(gf) /* Joerg Arndt, Jul 06 2011 */
    
  • Sage
    # uses[EulerTransform from A166861] and prepends a(0) = 1.
    a = EulerTransform(lambda n: n*(n+1)*(n+2)//6)
    print([a(n) for n in range(33)]) # Peter Luschny, Nov 17 2022

Formula

a(n) ~ Zeta(5)^(379/3600) / (2^(521/1800) * sqrt(5*Pi) * n^(2179/3600)) * exp(Zeta'(-1)/3 - Zeta(3) / (8*Pi^2) - Pi^16 / (3110400000 * Zeta(5)^3) + Pi^8*Zeta(3) / (216000 * Zeta(5)^2) - Zeta(3)^2 / (90*Zeta(5)) + Zeta'(-3)/6 + (Pi^12 / (10800000 * 2^(2/5) * Zeta(5)^(11/5)) - Pi^4 * Zeta(3) / (900 * 2^(2/5) * Zeta(5)^(6/5))) * n^(1/5) + (Zeta(3) / (3 * 2^(4/5) * Zeta(5)^(2/5)) - Pi^8 / (36000 * 2^(4/5) * Zeta(5)^(7/5))) * n^(2/5) + Pi^4 / (180 * 2^(1/5) * Zeta(5)^(3/5)) * n^(3/5) + 5*Zeta(5)^(1/5) / 2^(8/5) * n^(4/5)). - Vaclav Kotesovec, Mar 12 2015

A259068 Decimal expansion of zeta'(-3) (the derivative of Riemann's zeta function at -3).

Original entry on oeis.org

0, 0, 5, 3, 7, 8, 5, 7, 6, 3, 5, 7, 7, 7, 4, 3, 0, 1, 1, 4, 4, 4, 1, 6, 9, 7, 4, 2, 1, 0, 4, 1, 3, 8, 4, 2, 8, 9, 5, 6, 6, 4, 4, 3, 9, 7, 4, 2, 2, 9, 5, 5, 0, 7, 0, 5, 9, 4, 4, 7, 0, 2, 3, 2, 2, 3, 3, 2, 4, 5, 0, 1, 9, 9, 7, 9, 2, 4, 0, 6, 9, 5, 8, 6, 0, 9, 5, 1, 0, 3, 8, 7, 0, 8, 2, 5, 6, 8, 3, 2, 6, 7, 1, 2, 2, 4, 3
Offset: 0

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Author

Jean-François Alcover, Jun 18 2015

Keywords

Examples

			0.0053785763577743011444169742104138428956644397422955070594470232233245...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.15.1 Generalized Glaisher constants, p. 136-137.

Crossrefs

Programs

  • Mathematica
    Join[{0, 0}, RealDigits[Zeta'[-3], 10, 105] // First]

Formula

zeta'(-n) = (BernoulliB(n+1)*HarmonicNumber(n))/(n+1) - log(A(n)), where A(n) is the n-th Bendersky constant, that is the n-th generalized Glaisher constant.
zeta'(-3) = -11/720 - log(A(3)), where A(3) is A243263.
Equals -11/720 + (gamma + log(2*Pi))/120 - 3*Zeta'(4)/(4*Pi^4), where gamma is the Euler-Mascheroni constant A001620. - Vaclav Kotesovec, Jul 24 2015

A000417 Euler transform of A000389.

Original entry on oeis.org

1, 7, 28, 105, 357, 1232, 4067, 13301, 42357, 132845, 409262, 1243767, 3727360, 11036649, 32300795, 93538278, 268164868, 761656685, 2144259516, 5986658951, 16583102077, 45593269265, 124464561544, 337479729179, 909156910290, 2434121462871, 6478440788169
Offset: 1

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Author

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References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: a:= etr(n-> binomial(n+4,5)): seq(a(n), n=1..30); # Alois P. Heinz, Sep 08 2008
  • Mathematica
    nn = 100; b = Table[Binomial[n, 5], {n, 5, nn + 5}]; Rest[CoefficientList[Series[Product[1/(1 - x^m)^b[[m]], {m, nn}], {x, 0, nn}], x]] (* T. D. Noe, Jun 20 2012 *)
  • PARI
    a(n)=if(n<0, 0, polcoeff(exp(sum(k=1, n, x^k/(1-x^k)^6/k, x*O(x^n))), n)) /* Joerg Arndt, Apr 16 2010 */

Formula

a(n) ~ (3*Zeta(7))^(31103/423360) / (2^(180577/423360) * sqrt(7*Pi) * n^(242783/423360)) * exp(Zeta'(-1)/5 - 5*Zeta(3)/(48*Pi^2) + Zeta(5)/(16*Pi^4) - Pi^36/(1162964338810860915 * Zeta(7)^5) + Pi^24 * Zeta(5) / (413420708484 * Zeta(7)^4) - Pi^22 / (137806902828 * Zeta(7)^3) - Pi^12 * Zeta(5)^2 / (551124 * Zeta(7)^3) + Pi^12 * Zeta(3) / (11252115 * Zeta(7)^2) + Pi^10 * Zeta(5) / (122472 * Zeta(7)^2) + 49*Zeta(5)^3 / (216 * Zeta(7)^2) - Pi^8 / (108864 * Zeta(7)) - Zeta(3) * Zeta(5) / (15*Zeta(7)) + Zeta'(-5)/120 + 7*Zeta'(-3)/24 + (22 * 2^(6/7) * Pi^30 / (46901442470561469 * 3^(1/7) * Zeta(7)^(29/7)) - 10 * 2^(6/7) * Pi^18 * Zeta(5) / (8931928887 * 3^(1/7) * Zeta(7)^(22/7)) + Pi^16 / (141776649 * 6^(1/7) * Zeta(7)^(15/7)) + 2^(6/7) * Pi^6 * Zeta(5)^2 / (1701 * 3^(1/7) * Zeta(7)^(15/7)) - 2^(6/7) * Pi^6 * Zeta(3) / (19845 * 3^(1/7) * Zeta(7)^(8/7)) - Pi^4 * Zeta(5) / (216 * 6^(1/7) * Zeta(7)^(8/7))) * n^(1/7) + (-2 * 2^(5/7) * Pi^24 / (3938980639167 * 3^(2/7) * Zeta(7)^(23/7)) + Pi^12 * Zeta(5) / (500094 * 6^(2/7) * Zeta(7)^(16/7)) - Pi^10 / (142884 * 6^(2/7) * Zeta(7)^(9/7)) - 7*Zeta(5)^2 / (12 * 6^(2/7) * Zeta(7)^(9/7)) + Zeta(3)/(5 * (6*Zeta(7))^(2/7))) * n^(2/7) + (5 * 2^(4/7) * Pi^18 / (8931928887 * 3^(3/7) * Zeta(7)^(17/7)) - Pi^6 * Zeta(5) / (567 * 6^(3/7) * Zeta(7)^(10/7)) + Pi^4 / (108 * (6*Zeta(7))^(3/7))) * n^(3/7) + (-Pi^12 / (750141 * 6^(4/7) * Zeta(7)^(11/7)) + 7*Zeta(5) / (4 * (6 * Zeta(7))^(4/7))) * n^(4/7) + 2^(2/7) * Pi^6 / (945 * (3*Zeta(7))^(5/7)) * n^(5/7) + 7*Zeta(7)^(1/7) / 6^(6/7) * n^(6/7)). - Vaclav Kotesovec, Mar 12 2015

Extensions

More terms from Sean A. Irvine, Nov 14 2010

A000428 Euler transform of A000579.

Original entry on oeis.org

1, 8, 36, 148, 554, 2094, 7624, 27428, 96231, 332159, 1126792, 3769418, 12437966, 40544836, 130643734, 416494314, 1314512589, 4110009734, 12737116845, 39144344587, 119350793207, 361173596536, 1085171968872
Offset: 1

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Keywords

Comments

In general, if g.f. = Product_{k>=1} 1/(1-x^k)^binomial(k+m-2,m-1) and m >= 1, then log(a(n)) ~ (m+1) * Zeta(m+1)^(1/(m+1)) * (n/m)^(m/(m+1)). - Vaclav Kotesovec, Mar 12 2015

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: a:= etr(n-> binomial(n+5,6)): seq(a(n), n=1..30); # Alois P. Heinz, Sep 08 2008
  • Mathematica
    nn = 30; b = Table[Binomial[n, 6], {n, 6, nn + 6}]; Rest[CoefficientList[Series[Product[1/(1 - x^m)^b[[m]], {m, nn}], {x, 0, nn}], x]] (* T. D. Noe, Jun 20 2012 *)
  • PARI
    a(n)=if(n<0, 0, polcoeff(exp(sum(k=1, n, x^k/(1-x^k)^7/k, x*O(x^n))), n)) /* Joerg Arndt, Apr 16 2010 */

A255965 Expansion of Product_{k>=1} 1/(1-x^k)^binomial(k+6,7).

Original entry on oeis.org

1, 1, 9, 45, 201, 819, 3357, 13329, 52215, 199686, 750733, 2774793, 10112184, 36357280, 129131448, 453379226, 1574884565, 5415956550, 18450934294, 62303210591, 208624947952, 693066815809, 2285129922950, 7480504628754, 24320897894515, 78557786077315
Offset: 0

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Author

Vaclav Kotesovec, Mar 12 2015

Keywords

Comments

In general, if g.f. = Product_{k>=1} 1/(1-x^k)^binomial(k+m-2,m-1) and m >= 1, then log(a(n)) ~ (m+1) * Zeta(m+1)^(1/(m+1)) * (n/m)^(m/(m+1)).

Crossrefs

Cf. A000041 (m=1), A000219 (m=2), A000294 (m=3), A000335 (m=4), A000391 (m=5), A000417 (m=6), A000428 (m=7).

Programs

  • Mathematica
    nmax=40; CoefficientList[Series[Product[1/(1-x^k)^(k*(k+1)*(k+2)*(k+3)*(k+4)*(k+5)*(k+6)/7!),{k,1,nmax}],{x,0,nmax}],x]

Formula

G.f.: exp(Sum_{k>=1} x^k/(k*(1 - x^k)^8)). - Ilya Gutkovskiy, May 28 2018

A305653 Expansion of Product_{k>=1} 1/(1 - x^k)^((k+1)*binomial(k+2,3)/2).

Original entry on oeis.org

1, 1, 7, 27, 98, 323, 1085, 3471, 10998, 33874, 102737, 305849, 897899, 2597822, 7423408, 20957775, 58524868, 161741013, 442705279, 1200718351, 3228796864, 8611973548, 22793714865, 59887897679, 156252738062, 404964879419, 1042884107691, 2669317020743, 6792321636929
Offset: 0

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Author

Ilya Gutkovskiy, Jun 07 2018

Keywords

Comments

Euler transform of A002415, shifted left one place.

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(a(n-j)*add(d^2*
          (d+2)*(d+1)^2/12, d=numtheory[divisors](j)), j=1..n)/n)
        end:
    seq(a(n), n=0..35);  # Alois P. Heinz, Jun 07 2018
  • Mathematica
    nmax = 28; CoefficientList[Series[Product[1/(1 - x^k)^((k + 1) Binomial[k + 2, 3]/2), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 28; CoefficientList[Series[Exp[Sum[x^k (1 + x^k)/(k (1 - x^k)^5), {k, 1, nmax}]], {x, 0, nmax}], x]
    a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d^2 (d + 1)^2 (d + 2)/12, {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 28}]

Formula

G.f.: Product_{k>=1} 1/(1 - x^k)^A002415(k+1).
G.f.: exp(Sum_{k>=1} x^k*(1 + x^k)/(k*(1 - x^k)^5)).
a(n) ~ exp(Zeta'(-1)/6 - Zeta(3) / (4*Pi^2) + 149*Zeta(5) / (32*Pi^4) + 15876 * Zeta(3) * Zeta(5)^2 / Pi^12 - 666792 * Zeta(5)^3 / Pi^14 + 108884466432 * Zeta(5)^5 / (5*Pi^24) + Zeta'(-3)/3 + (-7*(7/2)^(1/6) * Pi / (384*sqrt(3)) - 21 * 2^(5/6) * sqrt(3) * 7^(1/6) * Zeta(3) * Zeta(5) / Pi^7 + 3087 * sqrt(3) * (7/2)^(1/6) * Zeta(5)^2 / (2*Pi^9) - 30339036 * 2^(5/6) * sqrt(3) * 7^(1/6) * Zeta(5)^4 / Pi^19) * n^(1/6) + ((7/2)^(1/3) * Zeta(3) / (2*Pi^2) - 21 * (7/2)^(1/3) * Zeta(5) / (2*Pi^4) + 254016 * 2^(2/3) * 7^(1/3) * Zeta(5)^3 / Pi^14) * n^(1/3) + (sqrt(7/6) * Pi / 12 - 756 * sqrt(42) * Zeta(5)^2 / Pi^9) * sqrt(n) + (9 * 2^(1/3) * 7^(2/3) * Zeta(5) / Pi^4) * n^(2/3) + (2 * (2/7)^(1/6) * sqrt(3) * Pi) / 5 * n^(5/6)) * Pi^(1/90) / (2^(247/270) * 3^(34/45) * 7^(23/270) * n^(79/135)). - Vaclav Kotesovec, Jun 08 2018

A007328 Difference between the number of 5-dimensional partitions of n and an approximation derived from binomial(n,4).

Original entry on oeis.org

0, 0, 0, 0, 0, 15, 75, 310, 1060, 3281, 9564, 26719, 72239, 191569, 500797, 1299925, 3362473, 8697198, 22513878, 58352126, 151267141, 391728632, 1011734975, 2602330120, 6657204192, 16920629023, 42697311397, 106912113623, 265560809521, 654270114555
Offset: 1

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Formula

a(n) = A000391(n) - A000390(n). - Sean A. Irvine, Dec 18 2017

Extensions

a(11)-a(21) from Sean A. Irvine, Dec 18 2017
More terms from Amiram Eldar, May 11 2024

A264925 G.f.: 1 / Product_{n>=0} (1 - x^(n+5))^((n+1)*(n+2)*(n+3)*(n+4)/4!).

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 5, 15, 35, 70, 127, 215, 360, 605, 1080, 2003, 3890, 7570, 14715, 27960, 52255, 95705, 173295, 311060, 557400, 999032, 1795880, 3235130, 5835955, 10521060, 18931287, 33956485, 60692510, 108087835, 191883595, 339724144, 600203700, 1058605775, 1864535670, 3279862975, 5762287759, 10109925380
Offset: 0

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Author

Paul D. Hanna, Nov 28 2015

Keywords

Comments

Number of partitions of n objects of 5 colors, where each part must contain at least one of each color. [Conjecture - see comment by Franklin T. Adams-Watters in A052847].

Examples

			G.f.: A(x) = 1 + x^5 + 5*x^6 + 15*x^7 + 35*x^8 + 70*x^9 + 127*x^10 + 215*x^11 + 360*x^12 +...
where
1/A(x) = (1-x^5) * (1-x^6)^5 * (1-x^7)^15 * (1-x^8)^35 * (1-x^9)^70 * (1-x^10)^126 * (1-x^11)^210 * (1-x^12)^330 * (1-x^13)^495 *...
Also,
log(A(x)) = (x/(1-x))^5 + (x^2/(1-x^2))^5/2 + (x^3/(1-x^3))^5/3 + (x^4/(1-x^4))^5/4 + (x^5/(1-x^5))^5/5 + (x^6/(1-x^6))^5/6 +...
		

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[1/(1-x^k)^((k-4)*(k-3)*(k-2)*(k-1)/24), {k,1,nmax}], {x,0,nmax}], x] (* Vaclav Kotesovec, Dec 09 2015 *)
  • PARI
    {a(n) = my(A=1); A = prod(k=0,n, 1/(1 - x^(k+4) +x*O(x^n) )^((k+1)*(k+2)*(k+3)/3!) ); polcoeff(A,n)}
    for(n=0,50,print1(a(n),", "))
    
  • PARI
    {a(n) = my(A=1); A = exp( sum(k=1,n+1, (x^k/(1 - x^k))^4 /k +x*O(x^n) ) ); polcoeff(A,n)}
    for(n=0,50,print1(a(n),", "))
    
  • PARI
    {L(n) = sumdiv(n,d, d*(d-1)*(d-2)*(d-3)*(d-4)/4!)}
    {a(n) = my(A=1); A = exp( sum(k=1,n+1, L(k) * x^k/k +x*O(x^n) ) ); polcoeff(A,n)}
    for(n=0,50,print1(a(n),", "))

Formula

G.f.: exp( Sum_{n>=1} ( x^n/(1-x^n) )^5 /n ).
G.f.: exp( Sum_{n>=1} L(n) * x^n/n ), where L(n) = Sum_{d|n} d*(d-1)*(d-2)*(d-3)*(d-4)/4!.
a(n) ~ Pi^(95/288) / (2 * 3^(527/576) * 7^(239/1728) * n^(1103/1728)) * exp(-25*Zeta'(-1)/12 - log(2*Pi)/2 + 595*Zeta(3)/(48*Pi^2) - 29291*Zeta(5) / (128*Pi^4) - 2480625 * Zeta(3) * Zeta(5)^2 / (2*Pi^12) + 72930375 * Zeta(5)^3 / (2*Pi^14) - 1063324867500 * Zeta(5)^5/Pi^24 - 5*Zeta'(-3)/12 + (41 * 7^(1/6) * Pi/(768*sqrt(3)) - 2625 * sqrt(3) * 7^(1/6) * Zeta(3) * Zeta(5)/(2*Pi^7) + 540225 * sqrt(3) * 7^(1/6) * Zeta(5)^2/(16*Pi^9) - 4740474375 * sqrt(3) * 7^(1/6) * Zeta(5)^4/(4*Pi^19)) * n^(1/6) + (-25 * 7^(1/3) * Zeta(3)/(4*Pi^2) + 735 * 7^(1/3) * Zeta(5) /(8*Pi^4) - 3969000 * 7^(1/3) * Zeta(5)^3 / Pi^14) * n^(1/3) + (7*sqrt(7/3)*Pi/24 - 4725 * sqrt(21) * Zeta(5)^2 / Pi^9) * sqrt(n) - 45 * 7^(2/3) * Zeta(5)/(2*Pi^4) * n^(2/3) + 2*sqrt(3)*Pi / (5*7^(1/6)) * n^(5/6)). - Vaclav Kotesovec, Dec 09 2015

A344204 Dirichlet g.f.: Product_{k>=2} 1 / (1 - k^(-s))^binomial(k+3,4).

Original entry on oeis.org

1, 5, 15, 50, 70, 201, 210, 540, 615, 1065, 1001, 2745, 1820, 3430, 4110, 6751, 4845, 10950, 7315, 15930, 13776, 17655, 14950, 38775, 22960, 32851, 35510, 53865, 35960, 81015, 46376, 92741, 73920, 90270, 88515, 180852, 91390, 137845, 139230, 241235, 135751
Offset: 1

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Author

Ilya Gutkovskiy, May 11 2021

Keywords

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